Brake



E. V. TAYLOR Dec. 19K, 1933.

BRAKE Filed Sept. 7. 1929 2 Sheets-Sheet 1 INVENTOR. lf'lg'elw )l77413101 BY ,Z/Q. yyn/ ATToR EY.

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E. vi TAYLOR 1,940,468

BRAKE Filed sept'. 7, 1929 2 Sheets-Sheet 2 52 52 sa y es 56 eq J `INVENToR.

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ATToR EY Patented Dec. 19, 1933 UNITED STATES PATENT OFFICE dix BrakeCompany, poration of Illinois South Bend, Ind., a cor- ApplicationSeptember 7, 1929. Serial No. 390,868

Claims.

This invention relates to brakes and is illustrated as embodied in aninternal expanding type of automotive brake. f

An object of the invention is to provide a very 5 simple and yeteiiicient type of applying means for the friction elements of the brakeand, in

the embodiments of my invention disclosedf there is disclosed a commonmeans for applying equal pressures to two cam devices adapted to renderoperative the friction elements, and which devices have l'lxedmountings, each acting on its adjacent end of the friction means.

According to one embodiment of the applying means, two separate anddistinct cams are mounted on a common support, each contacting with oneend of a contiguous friction element and both adapted to bel angularlyactuated by a fluid, said fluid supplied from a common source. The camsare preferably each keyed to a separate shaft, which shafts also supportgear members, the iiuid from the common source impinging upon the teethof the respective gears.

According to a second embodiment of my invention, two separate cammembers contacting with their respective friction elements of the brakeare adapted to be individually connected with a common pressureequalizing bar, the latter being bodily movable by transmission linkageto the respective service pedal, said bar balancing the forcestransmitted from the cams.

The above and other objects and features of the invention, includingspeciiiclnovel details of construction and combinations of parts, willbecome apparent from the detailed explanation of the embodimentsdisclosed in the drawings, in which:

Figure 1 is a View in side elevation of one form of brake employing mynovel actuator;

Figure 2 is a partial bottom plan view of the actuating mechani m ofFigure 1 looking in the direction of the arrows on the line 2-2 thereof;

Figure 3 is a section taken through the actuator of Figure 1 on the line3-3 thereof;

lFigure 4 is a view generally similar to Figure 1 showing in elevation asomewhat diierent type of brake with a hydraulic motor type of actuator;and

Figure 5 is a section taken on the line 5 5 of Figure 1 showing in moredetail the structure of the actuator of Figure 4.

In that embodiment of my invention disclosed in Figures l to 3,inclusive, I have disclosed an internal expanding type of brake,preferably comprising two shoes, 14 and 16, pivotally mounted on ananchor pivot 18 xedly secured to the backing or supportiplate 20 of thebrake. The important feature of the invention resides in the novelactuating means for the shoes 14 and 16, which preferably comprises ahorizontally extending equalizing link 22 having inclined thrust links60 24 pivotally mounted in slots in the enlarged ends thereof, whichlinks may be keyed to cam shafts 26, which shafts may have keyed theretothe shoe operating cams 28. Each of cams 28, shaped as half disks, ispreferably provided with a rib 30 65 on its curved or applying side,which rib is adapted to fit within a slot in the end of its contiguousbrake shoe, the slot being formed by extending parallel reinforcing andcam follower stampings 32 which are preferably projection welded on 70each side of the web of the shoe.

A reinforcing plate 34 may be provided between the ends of the armssecured to the cam shaft and the backing plate, as disclosed in Figure3, the cam shaft continuing through said plate and backingn plate andsecured thereto by cotter pins 36 as disclosed. The equalizing lever bar22 is adapted to be moved upwardly to rotate the thrust links 24 by`means of a crank arm 38 pivotally secured to a thrust link 40 pivotedto the center s0 of the equalizing bar, the crank arm being secured to ashaft 42 journaled in the support plate and rotated by means of a crankarm 44 pivotally secured to transmission linkage 46 such as the usualbrake hookup. The equalizing bar 22 is further provided at its centerwith a post 48 adapted to contact stops 50 integrally or otherwiseixedly secured to the backing plate.

In operation actuation of the crank arm 38 from the service pedalconnections serves to move thebar 22 upwardly, which in turn rotates thearms 24 to eiect clockwise and counterclockwise rotation to therespective cams. The stops 50 serve to guide the movement of the barduring thisl upward movement. By virtue of the floating nature of thebar with respect to the crank arm 38, thrust links 40, and the slottedconnection with the arms 24, there is provided equalized or balancedapplying forces to the respective ends of the brake shoes. This equalityof force to the respective ends of the shoes is the desideratum in thistype of brake, in that with either direction of drum rotation there iseffected equal braking.

In the embodiment of my invention disclosed in Figures 4 and 5, separatecams are again pro- 105 vided for each brake shoe, which cams areinterchangeable and are each xedly mounted and actuated by equal forcessimilar in general to the operation as disclosed in the aforementionedembodiment. With this construction, cams 50 110 are preferablynon-rotatably mounted on the square-sectioned ends of cam shafts 52,each of the latter having an interrupted type of gear 56 mounted onitssquare-sectioned inner ends. The gears 56 rotate within cylindricalopenings in a relatively narrow fluid .containing cylinder 58 interposedbetween the ends of the brake shoes and the backing plate being iixedlysecured by bracket portions 60 to the latter. The fluid reservoirs inwhich the gears are mounted are preferably interconnected by ducts 461,which ducts preferably meet at their centers in a common duct 64 towhich a supply pipe 66 may be attached. As may be clearly seen inFigures 4 and 5, the bracket portions 60, the cylinders 58, the gears56, the shafts 52, and the cams 50 mounted on the shafts 52 constitute aseparate subassembly unit operable for applying the brakes and adaptedto be mounted on the backing plate adjacent to the ends of the frictionelement, and if desired to be removed from the wheel as a unit.

In operation, a suitable iiuid such as air or liquid and under pressureis adapted to pass through the ducts 6l impinging upon the sides of thelowermost tooth of each of the gears to rotate the same, 'therebyactuating the cams in opposite directions to apply the brake shoes. Anyloss of fluid by leakage past the teeth of the gear passes into ducts 68and thence into a common outlet port conducted back to the line or tothe uid reservoir. All parts of the operating mechanism beingsymmetrical with respect to a vertical line through the center of thebrake, it is obvious that due to the inherent equalization of pressureto the respective cams, equal forces will be applied to the respectiveshoes.

With this type of actuator a two-shoe brake of the full-wrapping orduo-servo type is used having an adjustable oating joint 70 more fullydescribed in the application of Vincent Bendix,

No. 159,806 filed January 8th, 1927. The shoes 76 and 78 of the brakeare adapted to be anchored on one or the other of the iixed anchorages80 depending upon the direction of drum rotation. Return springs 82 and84 serve to return the brake to an inoperative position within the brakedrum upon release of the fluid pressure.

I have thus provided in the two embodiments disclosed and described twoseparate and distinct symmetrically arranged cams each actuating itsrespective brake shoe, each cam being xedly mounted and rotatable bymeans applying equal or balanced forces to the respective cams. f

While two illustrative embodiments of th invention have been describedin detail, it is not my intention to limit the invention to thoseparticular embodiments or otherwise than by the terms of the appendedclaims.

I claim:

1. A brake comprising, in combination, a rotatable drum and frictionelements within said drum having spaced apart ends and means forapplying said friction elements into drum contact, said means positionedbetween said ends, said means comprising two symmetrically positionedand oppositely movable cams, each contacting with its respectivefriction element, and means for rotating said cams comprising a fluidunder pressure, a pair of gears upon which said fluid impinges, and apair of separate shafts each having one of the gears keyed upon an endthereof and each supporting one of the cams.

2. A brake comprising, in combination, a rotatable drum and frictionelements within said drum having spacedapart ends and means for applyingsaid friction elements into drum contact, said means positioned betweensaid ends, said means comprising two symmetrically positioned andoppositely movable cams, each contacting with its respective frictionelement and means for rotating said cams comprising a ud under pressure,a pair of gears upon which said fluid impinges, a pair having one of thegears supporting one of the cams, cylinders each having one therein andboth positioned said friction elements.

3. Applying means for an internal expanding brake comprising, incombination, interchangeable cams symmetrically disposed with respect tothe vertical center line of the brake, each of said cams adapted to berotated in opposite directions to apply elements of the brake by meansof a uid under pressure, gear members having teeth upon which said nuidimpinges, and means for rotating bers.

4. Applying means for an internal expanding brake comprising, incombination, interchangeable cams symmetrically disposed with respect tothe vertical center line of the brake, each of said cams adapted to berotated in opposite directions to apply elements of the brake by meansof a fluid under pressure, gear members having teeth upon which the uidimpinges, a single fluid motor having separate recesses in which saidgear members are housed, and means for rotating said cams connected tosaid gear members and housed within the recesses of the motor. X

5. In a brake mechanism of the class described, applying means in twoseparate parts adapted to apply equal forces and means for rotating saidparts comprising an interrupted gear for each part, said gears mountedfor angular movement in a common mounting and adapted to be rotated atequal rates by uid under pressure from keyed thereto and each and a pairof uid of the gears lying between the ends of ya common sourceimmediately adjacent said gears.

EUGENE V. TAYLOR.

of separate shafts each said cams connected to said gear mem-

